Liquid cationic formulations of household cleaners or fabric softeners are frequently aqueous or alcoholic formulations. To appropriately adapt the rheological properties of the respective formulation to the required use and the customer's request, it is customary to add additives influencing the viscosity to the formulation, These can be polymers, for example. WO 99/06455 A, for example, describes thickening agents for acid compositions that comprise cationic homopolymers having a content of cross-linking agents of 50 to 600 ppm. Suitable polymers are also described in WO 2004/050812 A1, for example.
However, it has been shown in the production of liquid formulations that it is not possible or difficult to continuously meter a corresponding polymer into the liquid cationic formulation, in particular when these are present in solid form. For this reason, liquid formulations are usually produced in a batch mixer. With batch production, however, a consistent quality across different batches can only be ensured with high complexity, so that a consistent quality of the liquid cationic formulation is possible only within certain limits. Differing concentrations of polymers, and thus quality differences, can also occur within a batch.
Cationic acrylic polymers have emerged as particularly suitable thickening agents. These are usually present as solids, for example in the form of a powder. Since the continuous metering of a powder is almost impossible to implement, solids are usually first dissolved in a suitable solvent, or suspended in a suspending agent, and then added as a solution, or as a suspension, to a liquid formulation. Liquids used as solvents or suspending agents are preferably those that are also present in the actual formulation, so as to achieve good miscibility. WO 2013/016029 A1, for example, discloses a method for producing a composition that comprises an agent for setting rheological properties. In this method, a rheology additive is dispersed in an anhydrous but water-miscible liquid carrier material, such as a surfactant, a humectant, a polymer, an oil, or mixtures thereof. Water-swellable polymers, non-water soluble crystalline polymers or the mixtures thereof are used as the rheology additive.
When suitable cationic acrylic polymers are now added to a solvent, which represents the main component of the liquid cationic formulation, these swell. This yields a viscous, rubber-like mass, which can no longer be added to the liquid cationic formulation in a continuous production method. A need therefore exists for an option to continuously produce a liquid cationic formulation, so as to enable a cost-effective production method that also enables a continuous consistent quality of the resultant product.
Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description of the invention and the appended claims, taken in conjunction with this background of the invention.